This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. The emerging importance of the TAAR1 receptor in modulating brain monoamine systems provides a strong rationale for determining whether polymorphic variation at the locus is functional and examining the significant similarities between human and rhesus monkeys, as well as other species. We have applied our laboratory's significant expertise in assessing TAAR1 function, polymorphism discovery in rhesus monkey genes associated with drug addiction and neuropsychiatric disorders, and genetic variant functional assessments to investigate of the TAAR1 locus. We identified novel genetic polymorphisms in both the rhesus monkey and human TAAR1, and have found that across species, only the caniform carnivores have a deleted gene. The gene family has seen expansions among certain mammals, notably rodents, and reductions in others, including primates. By placing the trace amine associated receptors in an evolutionary context we can better understand their function and their potential associations with behavior and neurological disease.